Integumentary - Chapter 4 Learning Objectives 1. What are the layers of the epidermis? ○ The layers of the epidermis include the stratum basale (the deepest portion of the epidermis), stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum (the most superficial portion of the epidermis).The epidermis provides a protective waterproof barrier that also keeps pathogens at bay and regulates body temperature. ○ 2. What type of tissue comprises epidermis? ○ The epidermis is composed of stratified squamous epithelium of the keratinized type. ○ 3. What is the integumentary system proper? What are the accessory organs? ○ The Integumentary System proper is the skin.The skin is the largest organ of the human body! Your integumentary system is your body's outer layer. The Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands. These organs and structures are your first line of defense against bacteria and help protect you from injury and sunlight. Your integumentary
system works with other systems in your body to keep it in balance. 4. What is meant by cutaneous membrane? ○ The cutaneous membrane is the technical term for our skin. The skin's primary role is to help protect the rest of the body's tissues and organs from physical damage such as abrasions, chemical damage such as detergents, and biological damage from microorganisms.These membranes are thin and help to reduce friction. ○ 5. Know the types of cells found in each layer? Also know the general characteristics of each layer and how that layer is important to the epidermis. ○ The epidermis has three main types of cell: Keratinocytes (skin cells) Melanocytes (pigment-producing cells) Langerhans cells (immune cells). ○ Squamous cells. The outermost layer continuously shed is called the stratum corneum. ○ Basal cells. Basal cells are found just under the squamous cells, at the base of the epidermis. ○ Melanocytes. Melanocytes are also found at the base of the epidermis and make melanin.
○ 6. Know the layers of the dermis? ○ The dermis is a connective tissue layer sandwiched between the epidermis and subcutaneous tissue. The dermis is a fibrous structure composed of collagen, elastic tissue, and other extracellular components that includes vasculature, nerve endings, hair follicles, and glands. The role of the dermis is to support and protect the skin and deeper layers, assist in thermoregulation, and aid in sensation. Fibroblasts are the primary cells within the dermis, but histiocytes, mast cells, and adipocytes also play important roles in maintaining the normal structure and function of the dermis. ○ The dermis is divided into two layers: the papillary dermis and the reticular dermis. The papillary dermis is the superficial layer, lying deep to the epidermis. ○ 7. Know the types of connective tissues found in the dermis? ○ The dermis is composed of three types of tissues that are present throughout the dermis rather than in layers: Collagen. Elastic tissue. Reticular fibers. The most common connective tissue is collagen.
○ 8. What kind of receptor cells are found in the dermis ○ A cutaneous receptor is the type of sensory receptor found in the skin ( the dermis or epidermis). They are a part of the somatosensory system. Cutaneous receptors include mechanoreceptors (pressure or distortion), nociceptors (pain), and thermoreceptors (temperature). ○ Four receptor structures of the glabrous skin provide this information: Merkel discs, Meissner corpuscles, Pacinian corpuscles, and Ruffini endings. ○ 9. Where do we find papillary and reticular layers? ○ The papillary dermis is the superficial layer, lying deep to the epidermis. The papillary dermis is composed of loose connective tissue that is highly vascular. The reticular layer is the deep layer, forming a thick layer of dense connective tissue that constitutes the bulk of the dermis.
○ 10. Know how fingerprints are formed? ○ Fingerprints are those little ridges on the tips of your fingers. They're essentially folds of the outer layer of skin, the epidermis. The “prints” themselves are the patterns of skin oils or dirt these ridges leave behind on a surface you've touched. Your fingerprints began to form before you were born. ○ 11. What is the function of the hypodermis? ○ The hypodermis consists of well-vascularized, loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage and provides insulation and cushioning for the integument. The hypodermis is the bottom layer of skin in your body. It has many important functions, including storing energy, connecting the dermis layer of your skin to your muscles and bones, insulating your body and protecting your body from harm. As you age, your hypodermis decreases in size, and your skin starts to sag. ○ 12. How do thick skin and thin skin differ? ○ Skin can either be thin or thick. The main difference is the thickness of the epidermis and dermis, which are the top two layers of skin. Thin skin covers most of the body and can vary in thinness, with the thinnest skin covering the eyelids. Thick skin is present on the soles of the feet and palms of the hands.
○ 13. What are human skin pigments? ○ The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. ○ 14. Be familiar with the types of glands associated with the skin. For example, Eccrine, Apocrine Mammary. ○ Eccrine sweat glands occur over most of the body and open directly onto the skin's surface. Apocrine glands open into the hair follicle, leading to the surface of the skin. Apocrine glands develop in areas with many hair follicles, such as on the scalp, armpits and groin.There are four types of exocrine glands within human skin —sudoriferous, sebaceous, ceruminous, and mammary glands. 15. Know the accessory structures associated with skin and their components. ○ Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands. These organs and structures are your first line of defense against bacteria and help protect you from injury and sunlight.
○ 16. Pathology : What are the characteristics of skin cancer? ABCD test ○ A large brownish spot with darker speckles. A mole that changes in color, size or feel or that bleeds. A small lesion with an irregular border and portions that appear red, pink, white, blue or blue-black. A painful lesion that itches or burn.Basal cell carcinoma. Basal cells are the round cells found in the lower epidermis. ... ○ Squamous cell carcinoma. Most of the epidermis is made up of flat, scale-like cells called squamous cells. ... ○ Merkel cell cancer. Merkel cell cancer is a highly aggressive, or fast-growing, rare cancer. ... ○ Melanoma. ○ 17. Be familiar with which skin cancer is the most dangerous and which is the least dangerous. ○ Melanoma is often called "the most serious skin cancer" because it has a tendency to spread. Melanoma can develop within a mole that you already have on your skin or appear suddenly as a dark spot on the skin that looks different from the rest. Most common form of skin cancer but the least dangerous. Appear
as round or flattened lump or scaly spots. Red, pale or pearly in colour. May become ulcerated, bleed and fail to heal; Basal Cell carcinoma. ○ 18. What Is The Anatomy Of A Hair Follicle?How Does Hair Grow? ○ The hair follicle begins at the surface of the epidermis. For follicles that produce terminal hairs, the hair follicle extends into the deep dermis, and sometimes even subcutis. Meanwhile, follicles producing vellus hairs extend only to the upper reticular dermis.Hair grows from a root at the bottom of a follicle under your skin. The blood in your scalp goes to the follicle and supplies oxygen and nutrients to the hair root, which helps your hair grow. As your hair grows, it will push through your skin and pass by an oil gland. ○ 19. What Is An Erector Pili Muscle? ○ Arrector Pili Muscle - This is a tiny muscle that attaches to the base of a hair follicle at one end and to dermal tissue on the other end. In order to generate heat when the body is cold, the arrector pili muscles contract all at once, causing the hair to "stand up straight" on the skin. ○ The arrector pili muscle (APM) consists of a small band of smooth muscle that connects the hair follicle to the connective tissue of the basement membrane.
○ 20. What are the 3 different types of hair that grow on a person throughout his/her life? What happens to hair as we age? ○ At any given time, a random number of hairs will be in one of three stages of growth and shedding: anagen, catagen, and telogen.The first three phases — anagen, catagen, and telogen — cover the growth and maturation of hair and the activity of the hair follicles that produce individual hairs. During the final, or exogen, phase, “old” hair sheds, though usually, a new hair is getting ready to take its place. ○